Carburetor de-icing



United States Patent 3,503,723 CARBURETOR DE-ICING John D. Newkirk,Downers Grove, and Richard M. Miller, La Grange, Ill., assignors toNalco Chemical Company, Chicago, III., a corporation of Delaware NoDrawing. Continuation-impart of application Ser. No. 509,189, Nov. 22,1965. This application June 26, 1968, Ser. No. 740,034

Int. Cl. C101 N44 US. Cl. 4463 Claims ABSTRACT OF THE DISCLOSURECarburetor icing of internal combustion engines using voltatilehydrocarbon fuels is prevented by treating such fuels with aphosphorylated imidazoline composition.

This application is a continuation-in-part of my earlier filedco-pending application, Ser. No. 509,189, filed Nov. 22, 1965, nowabandoned.

BACKGROUND OF THE INVENTION The problem of carburetor throttle bladeicing and its attendant effect on the operation of internal combustionengines is well known. Poor engine performance in cold weather, asevidenced by stalling and bucking, is an experience shared by manymotorists who operate automobiles in many areas where intemperateweather conditions prevail during the winter months.

Five conditions are usually necessary to promote carburetor icing: (1)critical engine type, (2) low engine load, (3) air temperature fromapproximately 35 to 45 F., (4) 100% humidity and (5) volatilewinter-grade gasoline, that is, a gasoline having a Reid Vapor Pressureof at least lbs/sq. in. at 100 F. (A.'S.T.M. Method Designation D-323)and/or having a distillation curve such that at least 50% by volume ofsaid gas-oline distills over 212 F. When these circumstances concur, iceusually forms on the throttle blade and in the throttle blade opening,which in turn causes malfunctioning of the carburetor.

Improved carburetor design has not substantially alleviated thisproblem. One method of overcoming the difficulty is to add chemicalde-icers to the fuel. In most instances, these chemicals are composed oflower m0nohydric alcohols when used at dosages of l%2% or more, based onthe weight of the fuel. Such large dosages could naturally dilute thefuel, unless care is used in their addition. For this reason, it hasbecome popular to add the de-icer at the refinery level rather than tohave service station operators make the addition directly to the fueltank. It would be a valuable contribution to the art if a de-icingchemical were available which would be effective by adding very smallamounts to fuels used in internal combustion engines.

SUMMARY OF THE INVENTION In accordance with the invention, it has beenfound that carburetor icing may be avoided by adding to a volatilehydro-carbon liquid fuel burned in internal combustion engines ade-icing amount of the compositions of this invention.

The de-icing composition consists of an equimolar phosphorylatedcomposition having the formulae:

Where E is from the group consisting of:

3,503,723 Patented Mar. 31, 1970 (A) a l-alkan0l or alkylamineZ-substituted imidazoline radical, and

(B) a monohydric alcohol or an aliphatic primary amine having 1-18carbon atoms with the proviso that at least 3 occurrences of E are (A).

In a preferred embodiment, E is entirely the l-alkanol- 2-substituttedimidazoline radical.

Since the compositions contain free acid and amine groups, a certainamount of salt formation occurs when the compositions are in the form ofa solution.

It has also been found that the phosphorylated composition of thisinvention may be used as a gasoline detergent.

OBJECTS It is an object of this invention to provide a new chemicalprocess for preventing the icing of carburetors.

.Another object is to prevent carburetor icing by adding to the fuelsmall, yet effective, amounts of a chemical de-icer.

Other objects will appear hereinafter.

INVENTION The first starting material to produce the de-icingcomposition is a phosphorous compound calculated as P 0 A Wide varietyof phosphorous containing acidic compounds may be used, such asphosphoric acid, phosphorous oxychloride, phosphorous anhydride, etc.Most preferred for the purposes of this invention is phosphorouspentoxide.

The second component which is used to form the deicing composition ofthis invention is a l-alkanol, or alkylamino 2-substituted imidazolinewhich is defined by the following formula:

where R is an aliphatic group of 122 carbon atoms in chain length, Y andZ are selected from the group consisting of hydrogen and lower aliphatichydrocarbon groups of not more than 6 carbon atoms in chain length, R isan alkylene radical of 1-6 carbon atoms, Q is either 0 or NH, and n isan integer of 1-50.

When Q is O, the corresponding alkanol imidazolines may be formedgenerally by the reaction of alkanol amines such as aminoethylethanolamine and the like, with a fatty acid under conditions whicheffect ring closure. Broadly defined, the fatty acids which are usefulin the invention are those fatty acids having from 12 to 24 carbonatoms, which are liquid at room temperature. Specific examples of fattyacids which may be used are myristoleic acid, palmitoleic acid, oleicacid, linoleic acid, linolenic acid and ricinolenic acid. Also useful asfatty acids in this invention are many of the mixed fatty acids, such asdistilled coconut fatty acid, red oil fatty acid, vegetable fatty acidssuch as distilled cotton-seed fatty acid, distilled soybean andfractionated soybean fatty acid, tall oil fatty acid, distilled linseedfatty acid and the like. The mixed fatty acids are lower in cost andtherefore constitute a preferred species for use in this invention. Alsopreferred is oleic acid.

Two typical alkanol imidazodlines which may be used in the process ofthis invention are 1-(2-hydroxyethyl)-2- coco imidazaline and1-(2-hydroxyethyl)-2-tall oil imidazoline, both of which compounds areconveniently pre- 3 pared using the teachings of Wilson US. 2,267,965.Other types of typical imidazolines which may be used are:

Imidazolines having the above formula, where the substituted groups arethose radicals having between 12 and 22 carbon atoms, either substitutedor unsubstituted, are particularly suitable. Especially preferredradicals are heptadecenyl, heptadecadienyl, heptadecyl and pentadecylradicals and mixtures thereof.

When Q is NH, the corresponding imidazolines may be formed generally bythe reaction of an amine such as diethylenetriamine and the like with afatty acid under conditions which effect ring closure. Broadly defined,the fatty acids with which the amine may be reacted are those havingfrom 12 to 24 carbon atoms, which are liquid at room temperature.Specific examples of such fatty acids are the same as those listedabove.

Two typical alkylamino imidazolines which may be used in the process ofthis invention are 1-(2-aminoethyl)- 2-coco imidazoline and1-(2-aminoethyl)-2-tall oil imidazoline. Other types of typicalimidazolines which may be used are:

( 1) 1-(2-aminoethyl)-2-undecyl imidazoline; (2)1-(Z-aminoethyl)-2-tridecyl imidazoline;

(3) 1-(2-aminoethyl)--2-pentadecyl imidazoline; (4)1-(2-aminoethyl)-2-heptadecyl imidazoline.

Alkylamino imidazolines having the above formula, where the substitutedgroups are those radicals having between 12 and 22 carbon atoms, eithersubstituted or unsubstituted, are particularly suitable. Especiallypreferred radicals are heptadecenyl, heptadecadienyl, heptadecyl andpentadecyl radicals and mixtures thereof.

The reaction between P40 and l-alkanol or alkylamino 2-substitutedimidazoline takes place at a temperature of about 130-180 C. for 1-3hours. It yields in equimolar proportions the following products:

The identification of R, R Q, Y, and Z has been given above.

When the reactant composition includes a monohydric alcohol then 6 molesof imidazoline per mole of P 0 are not required.

It has been found to be absolutely essential that the mole ratio of A:B,as described above, range from no less than 1:3 to 1:6 since at least 3moles of imidazoline per mole of P 0 are necessary to impart de-icingactivity to the resulting de-icing composition. When less than 6 molesof imidazoline are used, it is also essential to provide a thirdcompound which will react at a temperature of 120-180 C. for a period of3-4 hours with the remaining bonds in the P 0 molecule.

Monohydric alcohols have been found to be surprisingly effective as athird reactant. The amount of alcohol required to form the compounds ofthis invention may be therefore defined as being that amount sufiicientto provide a mole ratio of starting reactants of A :B-l-C equal to 1:6when C represents the moles of monohydric alcohol present. Thus, if, forexample, 3 moles of the imidazoline are employed, an additional 3 molesof alcohol will be necessary. If 6 moles of imidazoline are employed permole of P 0 no alcohol will be necessary to satisfy the requirements setforth above.

If less than 6 but 3 or more moles of imidazoline per mole of P 0 areused, a monohydric alcohol is added to the reactant system such that thetotal moles of imidazoline and monohydric alcohol are 6 per mole of P 0used.

The referred to alcoholic reactants may be chosen from a wide variety ofmonohydric alcohols.

The classes of alcohols which are suitable for use are:

(1) Aliphatic alcohols (2) Alicyclic alcohols (3) Ethylenicallyunsaturated alcohols (4) Acetylinically unsaturated alcohols (5)Araliphatic alcohols (6) Aromatic-ethylenically unsaturated alcohols (7)Oxo alcohols Primary and secondary alcohols are greatly preferred.

Examples of the aliphatic alcohol reactants are ethyl, n-propyl,n-butyl, n-amyl, n-hexyl, n-heptyl, n-octyl, 11- nonyl, n-decyl,n-undecyl, n-dodecyl (lauryl), n-tetradecyl (myristyl), n-hexadecyl(cetyl), and n-octadecyl (stearyl); branched chain primary alcohols suchas isobutyl, isoamyl, 2-2,4-trimethyl-l-octanol and secondary alcoholssuch as isopropyl, sec-butyl, 2-pentanol, 2-octanol,4-methyl-2-pentanol, and 2,4-dimethyl-3-pentanol.

The alicyclic alcohols may be illustrated by cyclopentanol cyclohexanol,cycloheptanol and methanol.

Examples of ethylenically unsaturated alcohols are allyl, crotyl, oleyl,(cis-9-octandecen-10-ol), citronellol and geraniol,

Acetylencially unsaturated alcohols are illustrated by propargylalcohol.

Araliphatic alcohols are illustrated by benzyl, 2-phenylethanol,hydrocinamyl, and alpha-methyl-benzyl alcohols.

The aromatic-ethylenically unsaturated alcohols are illustrated bycinnamyl, where the replaceable hydrogen is on the alkyl group.

Oxo alcohols are normally a mixture of various intermediate molecularweight alcohols ranging from 4 to about 16 carbon atoms. Theirpreparation and description is described in the book Higher Oxo Alcoholsby L. F. Hatch, Enjay Company, Inc., 1957, which disclosure is herebyincorporated by reference. The general range of both alcohols and esterby-products typifying an oxo alcohol still bottom of the type which maybe used in the invention, is as follows:

Ingredient: Percent Mixed isoand n-octyl alcohol 2-20 Mixed isoandn-nonyl alcohol 5-40 Mixed isoand n-decyl and higher alcohols 25-90Esters 20-80 A typical oxo alcohol still bottom which finds excellentuse in preparing the compounds of the invention has the followingcomposition.

Ingredient Percent C alcohols 5 C alcohols 10 C and higher alcohols 35Esters 45 Soaps 5 vention is best accomplished by first reacting thephosphorous compound with the imidazoline. It is essential for thepurposes of this invention that at least 3 moles of the imidazoline permole of the phosphorous compound, calculated as P be employed. Excellentcompounds which show surprising ability as de-icing additives have beenprepared where the ratio of imidazoline to phos-. phorous compoundranges from 3:1 to 6:1.

To illustrate the preparation of a de-icing compound of this invention,the following is presented. One gram mole of phosphorous pentoxide,calculated as P 0 was added to kerosene to form a slurry. To thisslurry, 4 gram moles of 1 (Z-hydroxy-ethyl)-2-heptadecenyl-2-imidazolinewas slowly added with agitation. This mixture was then heated to about130 C. for 1% hours. At this point, the imidazoline had completelyreacted with the phosphorous compound. Then, two moles of oxo alcoholwere added and the mixture was heated at a temperature ranging from 100to 120 C. for 3 hours. The resulting solution was red-orange in color,was clear and had a concentration of approximately 25%. Later testing ofthis composition showed excellent de-icing properties.

While compositions as described above may be used as produced, it may bedesirable to dissolve them into a hydrocarbon liquid carrier, whichmakes proportioning of the treatment into the hydrocarbon fuel a simplematter. Such solvents as benzene, xylene, toluene, heptane and the likeare suitable for this purpose. Also, the wellknown blends offractionated aromatic petroleum based; products are economical choicesas solvents.

The amount of the de-icing composition which may be added to thevolatile hydrocarbon liquid fuel will vary, generally, upon a number offactors such as fuel volatility, local atmospheric conditions and thelike. The precise de-icing amount can readily be determined at therefinery by quality control operations. Normally, from about 5 p.p.m. toabout 500 p.p.m. of the reaction product of this invention willsatisfactorily prevent carburetor icing. A preferred range of thede-icing composi-' tion of this invention is from about p.p.m. to about100 p.p.m.

In order to demonstrate the utility of the invention, the followingexamples are presented.

EXAMPLES The following tests were conducted to determine the efficacy ofthe compositions of the invention as carburetor de-icers. The followingdescribes the test apparatus and methods employed in performing thesetests:

TEST EQUIPMENT Engine 1965 production, Falcon engine, equipped withfactory radiator, manifold, carburetor and automatic choke.

The following parts were removed or disconnected for reproductibilitypurposes: Air cleaner, radiator fan, thermostat and fast idle linkage,choke to throttle.

Test cell A 160 cubic foot capacity, refrigerated by CO -cooled Savasolwith automatic temperature control and manually controlled humiditywhich was equipped with remote engine controls.

DETAILED TEST PROCEDURE Test preparation Prior to starting the test, thefollowing was performed: (1) Drain engine fuel lines and carburetor.

(2) Check thermocouple performance.

(3) Stabilize temperatures as follows:

F. (a) Underhood (air) 36:2 (b) Oil sump 36:4 (c) Water jacket 36:4 (d)Carburetor air 36:2

6 (4) Establish 100% humidity. (5 Remove fuel from cold storage andconnect to fuel system.

(6) Start engine.

Test period 1) Accelerate to 1500 r.p.m., no load.

(2) Maintain 1500 r.p.m. for one minute.

(3) Reduce speed to idle. Allow 30 seconds idle time. If engine does notstall, repeat steps (1) through (3). During the 30 second period, noteengine bucking which would be indicative of ice formation, but withoutstalling. If engine stalls, record as such and restart engineimmediately, repeating steps 1) through (3). Record idle time in secondsbefore stall occurs.

(d) Items (1) through (3) constitute one cycle. Repeat as many cycles asnecessary until throttle plate temperature rises above freezing or untilthree cycles are completed without stalling indication.

(5) During the course of conducting items (1), (2) and (3), recordthrottle blade temperatures at the start of idle and at stall time, orend of idle. Record other temperatures (air, water and oil) immediatelyafter idle.

BASE FUEL DATA Composition, percent by volume: Percent Thermal cracked17 Catalytic cracked 12 Mixed aromatics 5 Alkylate 12 Pentanes 50Butanes 4 Specifications:

Gravity, API 65.6 ASTM gum, mgs./100 ml. .6 Sulphur, wt. percent .06

Tetraethyl lead, ml./ gallon 3.0 Octane number, motor method 87.8 Octanenumber, research method 96.7 Reid vapor pressure, 100 F. 11.7 Oxidationstability, minutes 1440 Distillation, ASTM:

IBP, F. 86 10% evaporated, F 108 20% 127 292 End point, F 358 Recovery,percent 97.0 Residue, percent 1.0 Loss, percent 2.0

TEST VARIABLES In brief, the operating conditions and procedures usedfor conducting the tests were as follows:

Conditions 35 to 40 intake air humidity Continuous air circulationProcedure (1) Start cold engine.

(2) Accelerate to 1500 r.p.m. and maintain for one minute.

(3) Decelerate to idle r.p.m. and maintain for one-half minute. Observeand record engine stalling characteristics.

(4) If engine stalls, immediately restart and rerun the cycles describedby items (1) through (3) above.

The engine, atmospheric conditions and operating procedure selected forthese studies were each planned to emphasize icing conditions so thatthe reduction of ice formation indicated by an additive would be furtherreduced by several times under normal consumer conditions.

Except that the engine load and speed must be low, the selection ofoptimum speeds for carburetor icing tests was relatively flexible. Ingeneral, the throttle opening should be at a minimum adjustment forprolonged engine warm-up and for maximum throttle blade exposure to themoist air; and yet, the throttle must be sufficiently opened to causeadequate fuel flow through the carburetors primary jets so that freezingtemperatures will result from vaporization of the volatile gasoline.

Engine speed to attain these conditions was established at 1500 r.p.m.and although ice formation began on the throttle blade at this speed,the engine seldom, if ever, stalled until the speed was reduced to idle.When decelerating from 1500 r.p.m. to idle, the air crack between thethrottle valve and throttle body began filling with ice, shutting offair into the manifold. Just prior to stalling, the air fuel ratio becameexcessively rich and occasionally caused the engine to buck beforestalling.

At temperatures below 35 F., the moisture content of the air isgenerally too low for the rapid build-up of ice necessary for stalling,but the maximum air temperature for stalling is not so well establishedbecause of the influence of fuel volatility and and carburetor design.Usually, standard procedure during carburetor icing tests is to maintainthe air temperature at a constant level throughout the test, at perhaps40 F. The temperature control technique used deviated from this standardprocedure since, during exploratory studies, it was observed that someadditive compositions were prone to cause irregular icing rates atdifferent temperature levels.

After conducting preliminary studies at constant temperatures, it wasdecided to try simulating consumer conditions by starting with a minimumair temperature of 35 F. and then allow a gradual rise in airtemperature to a maximum at which ice would no longer form. Althoughthis latter procedure introduced the problem of maintaining a constantair temperature increase rate, it appeared to provide a more valid,reproducible testing technique and was thus adopted as the procedure forthese tests.

Humidity was maintained at, or near, 100% through use of a finelyatomized water spray on the test cell cooling coils. Air circulationover these coils was held at a constant rate by means of a forcedair-recirculating system.

SUMMARY OF RESULTS Icing tests were conducted using a variety ofde-icing compositions. For control purposes, Run A was made in which node-icing compositions were employed. Run B represents a conventionaladdition of 1% isopropanol (10,000 p.p.m.). In Run C, a commercialmulti-purpose additive which is normally employed as a de-icing additiveand which comprises a l-alkanol, 2-alkyl imidazoline, was added at 15p.p.m. and at 30 p.p.m. The de-icing compositions of this invention werethen evaluated in a similar manner. The additive in Run D represents ade-icing composition formed from reacting phosphorous pentoxide, as Pwith 1-(2-hydroxyethyl)-2-heptadecenyl imidazoline followed by theaddito-in of octanol in a mole ratio of 1:412. Similarly, the de-icingcomposition used in Run E was a reaction product formed from the P 0 andimidazoline materials in a ratio of 1:6.

To demonstrate the surprising effectiveness of the deicing compositionsof this invention which are prepared with the specific mole ratios setforth above, other com positions were prepared with a mole ratio outsideof the ranges which represent the compounds of this invention.Specifically, the same starting material used in Run D were employed.Run F was made with a composition having a mole ratio of 1:1:5 while thecomposition of Run G was prepared using a mole ratio of 1:2:4.

All of the de-icing compositions were evaluated according to the testprocedure set forth above. The results of these tests are presentedbelow in Table I.

TABLE I.-DEIOING COMPOSITION EVALUATIONS De-ieer Amount, p.p.m. Numberof stalls Number of bucks As can be seen from the results presentedabove, the deicing compositions of this invention are surprisinglyeffective in reducing the number of stalls under conditions which aremost favorable for inducing icing difliculties in the operation ofinternal combustion engines. The de-icing compositions of thisinvention, Additives D and E, exhibit superior de-icing properties atsurprisingly low dosage. In contrast, compositions resulting fromstarting with the same reactants in ratios other than those which fallwithin the practice of this invention (F and G) show substantially noimprovement or advantage over a blank run involving no additive at all.

In addition to the compositions described above, various organic andinorganic salts thereof have also been seen to be equally effective asde-icing additives according to the process of this invention.Accordingly, it is contemplated that these materials fall within thespirit of this invention.

Having thus described the invention, what is claimed is:

1. A hydrocarbon motor fuel composition for preventing icing duringoperation of internal combustion engines consisting of (I) a majoramount of a hydrocarbon distillate in the gasoline distillation rangeand (II) 4-400 p.p.m. of an equimolar phosphorylated composition havin gthe formulae:

where E is from the group consisting of:

(A) a l-alkanol or alkylamino 2-substituted imidazoline radicalrepresented by the structure:

Y N-( JH all C 1Z (1 1iQ)ni RIQ where R is an aliphatic group of 1-22carbon atoms in chain length, Y and Z are selected from the groupconsisting of hydrogen and lower aliphatic hydrocarbon groups of notmore than 6 carbon atoms in chain length, R is an :alkylene radical of16 carbon atoms, Q is either 0 or NH and n is an integer of 150, and

(B) a monohydric alcohol or an aliphatic primary amine having from 1 to18 carbon atoms with the proviso that at least 3 occurrences of E are(A).

2. The composition of claim 1 where E is (A).

3. The composition of claim 1 where the alkanol group of saidimidazoline is 2-hydroxyethyl.

4. The composition of claim 3 where the 2-substituted group of saidimidazoline contains between 12 and 22 carbon atoms.

9 10 5. The composition of claim 4 where the 2-substituted 3,115,39712/1963 Fareri et a1 4463 group of said imidazoline contains from 15 to17 carbon 3,241,932 3/1966 Oblad 4463 atoms in an aliphatic chain.3,257,179 6/ 1966 Bott.

References Cited PATRICK P. GARVIN, Primary Examiner UNITED sTATEsPATENTS 5 Y. H. SMITH, Assistant Examiner 3,060,007 10/1962 Freedman4463 US. Cl. X.R.

3,098,727 7/1963 Hamer et a1. 4463 4476 23 UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent Nol 3 ,503,123 Dated march 11. 1Q70Inventor(s) John D. Newkirk et a1 It is certified that error appears inthe above-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 1, line 15, "voltatile" should read --volatile--,-, line 70, thatportion of the formula reading "0" 0 should read O Column 2, line 7,"Z-substitutted" should read --2-substituted--.

Column 3, line 50, that portion of the formula reading "N" should read NSIGNED AUG SEALED nus 1 819 MIMI!- IIIIIUII I. a. \tteningOffi Oomisaiow01' Pa

